Chronic obstructive pulmonary disease (COPD) causes an increase in the work of breathing that leads to dyspnea, respiratory muscle fatigue and general discomfort. One therapy for COPD patients is to provide continuous positive airway pressure (CPAP), wherein the patient's airways are maintained at a constant, positive pressure throughout their respiratory cycle. This type of therapy has been shown to effectively relieve hyperinflation and gas trapping in COPD patients thereby decreasing the inspiratory work of breathing. A downside is that CPAP devices may be bulky, which limits the portability of the device and consequently the mobility of the patient. In addition, CPAP devices require a facial interface, such as a mask or other device, which may cause discomfort and lead to poor patient compliance. In addition, CPAP devices require an energy source, whether electrical or pneumatic.
Alternatively, the benefits of CPAP may be achieved by surrounding the thorax of the user with negative pressure. Typically, such devices are configured with bulky external compressors, requiring a power supply, which may limit patient mobility and compliance.